Luka Binniyat has been remanded in custody by Kaduna State High Court after being accused of publishing a false report of an attack by nomadic Fulani herdsman.
Tony Blair visited Kaduna on Thursday - one day after Mr Binniyat was remanded. The Tony Blair Institute for Global Change has been working with officials to help make the state more democratic.
Christian Solidarity Worldwide (CSW) - a group supporting believers under pressure for their faith - says keeping Mr Binniyat in custody is "excessive", given his repeated attempts to have the article withdrawn.
CSW's Chief Executive Mervyn Thomas added: "We urge the Government of Kaduna State to respect freedom of expression, to end these seemingly malicious prosecutions and to prioritise tracing, disarming and prosecuting the killers; compensating and caring for survivors, and restoring occupied lands to their rightful owners.
"In addition, as the Tony Blair Institute for Global Change works with the state government to deliver democratic dividends, we urge it to also assist in addressing the challenges to rule of law posed by these arrests and prosecutions, encouraging respect for press freedom and advocating for protection and justice for targeted communities in southern Kaduna."
The case concerns an article Mr Binniyat wrote on 22nd January 2017 which included inaccurate information from a source. Numerous calls to his editor failed to get the article withdrawn. His employer, Vanguard Newspaper, has not been penalised.
CSW claims the case of Mr Binniyat highlights an eroding of press freedom and the inequality under the law of different religious groups. They claim Muslim pressure groups circulating incorrect information have not been prosecuted.
Following a not guilty plea by Mr Binniyat to charges of "incitement" and "injurious falsehood", his case was adjourned until Thursday 20th July. His arrest has been denounced by the Nigerian Union of Journalists.
Kaduna State has experienced numerous attacks by Fulani militia in the last year or so. At least 800 people were killed in 2016 alone.
Christian leaders, journalists and activists who have drawn attention to events in the area have been accused of "hate speech" or "incitement".
Mervyn Thomas added: "Such selective prosecutions not only undermine the rule of law, but also erode confidence in a state government that has yet to address the violence in southern Kaduna effectively, or to assist those displaced by the attacks."
Mr Binniyat is on crutches and medication following a car accident.